Ion exchangeable glass with fast diffusion

Abstract

Glasses that undergo rapid ion exchange. The glasses comprise SiO 2 , Al 2 O 3 , P 2 O 5 , Na 2 O, K 2 O, and, in some embodiments, at least one of MgO and ZnO. The glass may, for example, be ion exchanged in a molten KNO 3 salt bath in less than 1 hour at temperatures in a range from about 370° C. to about 390° C. to achieve a depth of surface compressive layer of greater than about 45 microns, or in a range from about 0.05t to about 0.22t, where t is the thickness of the glass. The glasses are fusion formable and, in some embodiments, compatible with zircon.

The invention claimed is: 
     
       1. A glass comprising:
 from greater than 57 mol % to 67 mol % SiO 2 ; 
 from 9 mol % to 18 mol % Al 2 O 3 ; 
 from 4 mol % to 8 mol % P 2 O 5 ; 
 from 13 mol % to 16 mol % Na 2 O; 
 from greater than 1 mol % to 5 mol % K 2 O; and 
 ZnO, 
 wherein (R 2 O(mol %)+R′O(mol %))−(Al 2 O 3 (mol %)+P 2 O 5 (mol %))<0, R 2 O=Li 2 O+Na 2 O+K 2 O+Rb 2 O+Cs 2 O, and P′O=ZnO+MgO+CaO+SrO+BaO, and 
 wherein the glass is substantially free of lithium. 
 
     
     
       2. The glass of  claim 1 , wherein the glass comprises greater than 60 mol % SiO 2 . 
     
     
       3. The glass of  claim 1 , wherein the glass comprises from 60 mol % to 65 mol % SiO 2 . 
     
     
       4. The glass of  claim 1 , wherein the glass comprises:
 greater than 57 mol % to 67 mol % SiO 2 ; 
 9 mol % to 18 mol % Al 2 O 3 ; 
 13 mol % to 16 mol % Na 2 O; and 
 greater than 0 mol % to less than 1 mol % MgO+ZnO, 
 wherein R 2 O+R′O is less than 18 mol %. 
 
     
     
       5. The glass of  claim 1 , wherein the glass comprises from 10 mol % to 15 mol % Al 2 O 3 . 
     
     
       6. The glass of  claim 1 , wherein the glass comprises from 4 mol % to 7 mol % P 2 O 5 . 
     
     
       7. The glass of  claim 1 , wherein the glass comprises from greater than 0 mol % to less than 0.1 mol % MgO+ZnO. 
     
     
       8. The glass of  claim 1 , wherein the glass is substantially free of MgO. 
     
     
       9. The glass of  claim 1 , wherein R 2 O+R′O is less than 18 mol %. 
     
     
       10. The glass of  claim 1 , wherein the glass is substantially free of B 2 O 3 . 
     
     
       11. The glass of  claim 1 , wherein the glass has a coefficient of thermal expansion of at least 92×10 −7 ° C. −1 . 
     
     
       12. The glass of  claim 1 , wherein the glass has a liquidus temperature T L , a 160kP temperature T 160kP , a 35 kP temperature T 35kP , and a zircon breakdown temperature T breakdown , wherein T L <T 160P  and T breakdown >T 35kP . 
     
     
       13. The glass of  claim 1 , wherein the glass has a compressive layer extending from a surface of the glass to a depth of compression of at least 45 μm. 
     
     
       14. The glass of  claim 13 , wherein the depth of compression is in a range from 45 μm up to 200 μm. 
     
     
       15. The glass of  claim 13 , wherein the glass has a thickness t and wherein the depth of compression is less than or equal to 0.22t. 
     
     
       16. The glass of  claim 13 , wherein the compressive layer comprises a compressive stress of at least 500 MPa. 
     
     
       17. A consumer electronic product, comprising:
 a housing having a front surface, a back surface and side surfaces; 
 electrical components provided at least partially within the housing, the electrical components including at least a controller, a memory, and a display, the display being provided at or adjacent the front surface of the housing; and 
 the glass of  claim 1  disposed over the display. 
 
     
     
       18. An ion exchanged glass comprising the glass of  claim 1 . 
     
     
       19. A consumer electronic product, comprising:
 a housing having a front surface, a back surface and side surfaces; 
 electrical components provided at least partially within the housing, the electrical components including at least a controller, a memory, and a display, the display being provided at or adjacent the front surface of the housing; and 
 the glass of  claim 18  disposed over the display.